ANS:D - all the above.

Transiting:

It is also known as plunging or reversing. It is the process of turning the telescope about its horizontal axis thought 180° in the vertical plane thus bringing it upside down and making it point exactly in opposite direction.

Swinging the Telescope:

It means turning the telescope about its vertical axis in the horizontal plane. A swing is called right or left according as the telescope is rotated clockwise or counterclockwise.

Face Left:

If the vertical circle of the instrument is on the left of the observer while taking a reading, the position is called the face left and the observation taken on the horizontal or the vertical circle in this position is known as the face left observation.

Face Right:

If the vertical circle of the instrument is on the right of the observer while taking a reading, the position is called the face light, and the observation taken on the horizontal or the vertical circle in this position is known as the face right observation.

Changing Face:

It is the operation of bringing the vertical circle to the right of the observer if originally it is to the left, and vice- versa. It is done in two steps: firstly revolve the telescope through 180° in a vertical plane and then rotate it through 180° in the horizontal plane i.e. first transit the telescope and then swing it through 180°.